It simply takes milliseconds of processing time to capture the image, process it, relay it and display it in the EVF. So for tasks like sports, birds in flight - anything that needs critical timing, the OVF is likely to be faster - probably always.

And so TV cameras will not be able to follow golf balls, hockey pucks, baseballs, etc. because they all use EVFs. Oh, wait...they have been doing that for years.

They have been doing it with analog. I haven't seen any digital cameras without lag. Someday soon no doubt but not yet.